[Storms and Convective discussion - August 2023]

17 minutes ago, Supacell said:

Where I can understand the frustrations of this year's storm season for some, can we please stay on topic and not derail this thread into a thread about the performances of the Met Office.

As for this evening, there is still a bit of uncertainty as to where any storms will occur or if any will occur at all. I was planning on chasing this evening despite the inevitable long drive. However I'm now not convinced the drive would be worth it.

Edit: Eastward shift on AROME 12z. Risk area now looks to be Kent and then grazing the coasts of Essex and southern Suffolk.

I have also decided to bail on a chase tonight given the uncertainties... to add further doubt into your mind  

[Storms and Convective discussion - August 2023]

15 minutes ago, Jamie M said:

Wessex Convection Experiment in full swing, can see em all on https://sondehub.org/

 

This seems to be a brilliant opportunity to get some very important data.

[Storms and Convective discussion - August 2023]

2 minutes ago, Turquoise said:

BBC weather forecast at 9pm last night....heavy rain and frequent lightning at 7am across the country. Its now 9am and still not a single strike anywhere in the country.

How do they always get it so wrong

 

Because elevated convection is one of the biggest challenges in forecasting at the moment  I hope they didn't use the word frequent lightning... eek!

[Storms and Convective discussion - August 2023]

10 minutes ago, DDDM said:

This matrix shows a high likelihood however as I type this first system has not resulted in a single strike on the U.K. mainland (as shown on either of the two main lighting maps). Therefore it can be argued that the likelihood should have been lower which would have resulted in no warning 

Warnings must only be issued when appropriate - in this case it was clearly not necessary. 

Yep, you do make a good point! Although, always easier to say in hindsight 

[Storms and Convective discussion - August 2023]

Judging by the models, I still think anywhere east of Cambridge is within a good chance at some lively thunderstorms tonight. Disappointing I know for the rest of us...

[Storms and Convective discussion - August 2023]

10 minutes ago, Alderc 2.0 said:

Come on Ben, this situation doesn’t warrant that warning, if it does a warnings need to be issued pretty much every time it rains. Warnings should be used for dangerous situations. 

This is the matrix for the warning, which only suggests a low impact scenario. I completely get you though, and normally I'm not the biggest fan of the Met Office warnings either. But I think given what the models were showing, this was a reasonable issuance of a low-end yellow warning. We can agree to disagree, I always respect your opinion.

 

[Storms and Convective discussion - August 2023]

4 minutes ago, Alderc 2.0 said:

Why’s the a metoffice warning for storms then?

Because torrential rain/flash-flooding and the occasional lightning strike produced by the storms can pose considerable risks to the general public during rush-hour.

[Storms and Convective discussion - August 2023]

Was only expecting sporadic strikes for the stuff this morning, so I don't think it was too far from general expectations. It does appear like the tongue instability struggled to advect far enough northwards however, with any lightning really being confined to the channel.

[Storms and Convective discussion - August 2023]

11 minutes ago, Harry said:

Interesting that the MetOffice only has a warning out for thunderstorms for 06:00 until 12:00 tomorrow. Perhaps like us they’re too baffled by the current model uncertainty 

Quite possibly but also, the thunderstorms at 06:00-12:00 will pose a risk to those travelling to work during rush hour etc. Whereas overnight thunderstorms pose much less of a risk to safety.

[Storms and Convective discussion - August 2023]

3 minutes ago, Harry's House said:

Don't know what the chances are of much if any thundery activity at Hamstreet, SW of Ashford. Been here for over a month now and still no thunder heard or lightning seen yet.

For similar setups like tomorrow night, elevated thunderstorms generally are most active across far SE UK (East Sussex/Kent). Therefore, I'd like to think you're in a pretty good position as it stands!

[Storms and Convective discussion - August 2023]

18 minutes ago, Badgers01 said:

What about Surrey ? Looks like we might be in with a chance ?

As it stands, I'd expect any lightning would be to the south and east of you and moving away all the time. Therefore, the risk of any lightning overhead is low but not nil.

[Storms and Convective discussion - August 2023]

2 hours ago, Thunders said:

live in Eastbourne, just east of Brighton,  would i still be able to see the storms if they were to hit n/nne of Brighton

They would be moving up from the south, so yes I think you might do quite well if all goes to plan. I'll have a think about whether it's worth chasing, but if I were Eastbourne would be a good shout.

[Storms and Convective discussion - August 2023]

22 minutes ago, Alderc 2.0 said:

Quite often with these setups they can wobble back westwards but that seems highly unlikely in this situation and goes against everything that has happened this summers.

18th May last year exceeded my expectations with regards to westward extent of lightning. I'd have to look for similarities between tomorrow night and this event.

[Storms and Convective discussion - August 2023]

Having a look at the models, tomorrow morning I have questions over how frequent on lightning will be. I'm expecting lightning to be relatively infrequent, but further S, say in the vicinity of IOW, (where instability is likely to be higher before fizzling out) there may be more frequent lightning for a time.

Tomorrow night is the main show, albeit only for the SE/E England. My best guess for a good lightning show would anywhere NNE-E of Brighton. Sporadic lightning further west, but at this point the majority of lightning will always be within the high Theta-W airmass.

[Model Output Discussion - Mid Summer Onwards]

30 minutes ago, minus10 said:

Gfs 6z continuing with its previous heatdome theme  throughout August for the southern half of the uk..

..not a complete outlier this time ...

...then culminating in a breakdown from a thundery low moving north..

..is this theme gathering momentum ?

Significantly better set of 06z ensembles vs the previous 0z, 18z and 12z respectively. Hopefully this is a trend going forward, for those that chase hot weather charts!

[Storms and Convective discussion - August 2023]

2 minutes ago, WeatherArc said:

Very good run from the 06z GFS

Widely 25+ temps across England will combine with 18 degree+ dew points and decently steep lapse rates (especially in the south)

This will result in around 1500 j/kg of sbcape across the central and southern parts of the country. 

Incredibly good bulk shear values will increase a possible supercellular threat especially in the central parts of the country where storms can tap into both the cape and the 50+ knot bulk shear.

However, a lack of low level shear may disrupt this threat, especially when combined with the weak effective inflow layer (I think this is the GFS overdoing things). If supercells do form i would expect them to be more of a  hail threat than anything tornadic. The only way i see cells becoming tornadic in these type of conditions would be through constructive storm mergers that can increase low level SRH.  

I did want to quickly mention this hodograph, 53 knots of 6km shear would favour LP (low precipitation)  supercells as strong upper level winds will allow for any precip to be ventilated away from the updraft base, could make for some pretty amazing views.

 

 

A classic loaded gun scenario here. EC 0z also going for some big storms next Tuesday, but more in the form of some very active elevated thunderstorms rather than surface-based activity. In the models can keep trending in the right direction, we might have a number of opportunities.

[Model Output Discussion - Mid Summer Onwards]

2 hours ago, Earthshine said:

Mega sweats from the ECMWF

Looking at the bigger picture, that's a really positive set of ensembles and around 15% or so, go warmer than the OP.

[Storms and Convective discussion - August 2023]

17 hours ago, matty40s said:

Sorry, some of your forecasts are so insignificant...perhaps stick to the major risks, or link to a website where you can explain your thinking.

I'm just trying to help, especially as you have such good knowledge and are so new to this. Constant storm forecasts of such wide areas at limited risks tends to dilute interest completely. Stick to larger outbreaks and major risks, dont feel the need to post daily.

..and most of all, enjoy what you do, learn, preach, and tell us all about it. Your enthusiasm is brill.

You're right, some of the forecasts are 'insignificant' but that is the nature of weather, more often than not the risk of a thunderstorm/lightning on any given day is going to be small/near-zero. I would actually encourage storm forecasts on insignificant days, as I admire the enthusiasm and they encourage conversation. Personally, if the limited risk days aren't of interest, then you don't have to read them.  

Some greater destabilisation looks to occur Friday night, but the warmest airmass is consistently being pushed further east, reducing the ceiling for big thunderstorms. Been very busy with work (as you might expect given the poor weather at the moment), but hopefully will have more time to have a greater look at Friday's risk.

[Model Output Discussion - Mid Summer Onwards]

EC 12z showing a very complex evolution next Sunday into Monday. The little disturbance prevents the Azores high from really building NE'wards across the UK, whereas the GFS produces a much cleaner evolution. It really wouldn't take much to send us into the furnace, but it's all up in the air at the moment.

[Model Output Discussion - Mid Summer Onwards]

You thought GFS & EC 12z were good... GFS 18z is on smoke. Would be a serious August heatwave. 20C at 850hPa skirting the south coast for at least a week from T186 and looks like it'll only get more extreme into fantasy land. A good spectacle, even if it is unrealistic.

[Storms and Convective discussion - July 2023]

On route to Stoke-on-Trent, then will go from there.

[Storms and Convective discussion - July 2023]

1 minute ago, Alderc said:

06Z even worse…..

Haha, fair! Not surprised that models are having difficulty getting a good grasp tbh.

[Storms and Convective discussion - July 2023]

2 minutes ago, Alderc said:

Can’t get a bigger fail than this.

Uh, fortunately Alderc that AROME chart displayed is 07UTC which would correspond to 08BST. So we've got an hour yet for these developments to kick off  

Latest radar frame would suggest dark echoes developing S of IOW.

[Storms and Convective discussion - July 2023]

Based on tonights runs, after earlier elevated thunderstorms locally, I will be heading up to Stoke-on-Trent to position myself for the afternoon convection. Seems like Manchester/Liverpool is right in the firing line tomorrow. 

Regarding the elevated thunderstorms tomorrow morning, could be anyones guess who sees them; but favouring CS/SE England, into East Midlands/E Anglia at the moment.

[Storms and Convective discussion - July 2023]

UKV seems to come in-line a little with the AROME for the surface-based activity tomorrow afternoon, but keeps the widespread elevated activity during the morning. If UKV comes to fruition this could be one of the most active thunderstorm days in a while.